Making maps for Virtual Tabletops using Photoshop and Roll20

So lets talk about Virtual Tabletops, I play in a Friday night game, I play in a Saturday day game and run a Saturday night game. Two of them used to be face to face, but currently all of these games run in Roll20.

If you’ve never run Roll20 before sign up for an account. At your home screen click Create New Game. Choose a name for your game and character sheet for your game system if they have one.

Roll20 Page Start New Game

“I’m ready create game”

Drop a file in the background if you’d like. This is the cover photo for your game.

“Launch Game”

Go to Settings (the Gear) on the far right, then scroll down to “Player Video/Avatar Size” set it to “Names Only” You don’t want to run video or audio through Roll20, you just need it to play the game. Many people run Skype calls or voice channels on Discord servers for the audio portion of their games.

Click “Page Toolbar” the light blue icon on the far right.

Roll20 Page Toolbar

When the toolbar drops down select “Page Settings” its the Blue and White gear icon to the left of your Start map.

Roll20 Page Toolbar Page Settings

In the Page Settings you can choose to change the color of the background or the color of the grid. You can also change the size of the map.

Roll20 Page Toolbar Page Settings Dialog

We’re going to need a map, so I’m switching tools for a second.

Now in Photoshop, I have a single deck from our Katar Heavy Freighter, my artist designed the ship around 1 inch square grids being equal to 5 ft and the grids are laid out on the floor of the ship. I have removed text labels and pointers as well as the white background.

I have put the Bridge level with transparent background onto its own image file and layer in Photoshop.

Turn on the Grid view in photoshop to overlay the image’s 1 inch grids with Photoshops print size rulers. I zoom in until I can see the grid intersections.

Select the layer with the map on it and move it with the mouse until the map grid and photoshop grid are pretty close. I use the arrow keys to fine tune the grid alignment.

Katar Heavy Freighter Bridge Demo Grid

I brought this image over from Illustrator by Exporting it to a PNG at 1,800 DPI. I have saved the PNG as a Photoshop PSD file. Each deck of the ship was originally a 1/4 page illustration. So I had to increase the size of the (5.5×3.5 inch) image by 4 to get the intended number of inches for the map. If you get the map with 1 square equals 1 inch in 300 DPI from your cartographer you will be ahead of the game. I added the Text label layer in the font we use for all of the Galaxy Pirates products and a starfield background beneath the deckplan layer. If this were a fantasy map I’d use a different font and parchment background.

If I want to print this map I would reduce the image size to 300 DPI for printing. That’s the usual standard for color printing.

For the image resizing you may want to have a hand calculator available, yes your computer has one, yes your phone has one, you may still want one that you can stare at your numbers while keeping the Photoshop or Roll20 dialog boxes open.

As we’re creating a map for Roll20, we’re going to reduce the image size to 70 DPI. Roll20 says in their instructions to set the maps to 72 DPI which is what web designers from the 90s had to set their images to in order to look good on screen for people with DSL and dialup internet. Roll20 also tells you that it will set 1 inch grids to a square 70×70 pixels by default. So I have been setting my VTT maps to 70 DPI.

Katar Heavy Freighter Bridge Demo Image Size

Katar Heavy Freighter Bridge Demo Grid 70 DPI

Now while I’ve been working in PSD and PNG for a lot of this, Roll20 says that some customers have CPU or GPU problems processing PNG files. So save your 70 DPI file as a JPEG and check the colors to ensure they aren’t faded due to the JPEG compression choosing a lousy color pallette for you. Roll20 also doesn’t want files over 10MB so I set the image quality to 10 out of 12 and it looks good without having too large a file size.

Go to Roll20 select your map in the Page Toolbar. Go to the toolbar on the left and choose the Cube under the Arrow icon, then choose the Map & Background layer. Drag your new map image into the screen.

Drag the image around until you can see the whole thing on the screen, you may need to use the zoom out feature to see the whole 25×25 area. The map should try to snap to the grid. Right click on the image, choose Advanced, choose Set Dimensions. Type in the dimensions of your image. In this case 1610×980

Roll20 Freighter Set Dimensions

If your math is right, drag the image to line up with the upper left corner and release. The Roll20 grid should lay over your internal map grid. Zoom in and look around.

If you have any comments or questions about this post, please let me know at: